The apparatus of this invention is used in screening samples of antibody solutions on nitrocellulose or other transfer membranes on which proteins or antigens have been immobilized. The membranes, commonly made of nitrocellulose paper-like sheets, carry proteins which have been electroblotted from polyacrylamide gels. The gel may include one sample that is electrophoresed across the entire gel and may be used for the screening of a number of antibodies against the same antigen pattern. Alternatively, antibodies may also be screened against different antigens electrophoresed in separate vertical lanes on the same gel.
A number of the same or different antibody solutions may be applied against a single transfer membrane and through suitable processing, observable results of the reactions can be used for a screening analysis.
In this type of screening, it is desirable to apply a relatively large number of separate rows or stripes of the sample solutions under assay upon a single transfer membrane for side-by-side reading of the test results. Also, it is normal for many test purposes to utilize transfer membranes having a relatively large number of different bands of immobilized anitgens located along the length of the membrane. In those instances, the stripes of antibody solutions are applied transversely to the numerous bands. Thus, observable test results occur at various locations along the lengths of the stripes where they intersect with the different bands. This provides side-by-side comparisons of antibody blotting profiles.
An apparatus for conducting such screening tests has been developed in which the transfer membrane, upon which the antigens have been immobilized, is positioned between a pair of plates that are fastened together. The uppermost plate has an array of parallel grooves or channels that open downwardly against the membrane. The channels may be filled with one or more different antibody samples so that parallel stripes of such samples are incubated on the membrane for the desired side-by-side comparisons.
The apparatus of this invention relates to improvements to the foregoing apparatus, particularly in reducing the amount of antibody sample solutions required for conducting the screening and in providing a maximum screening capacity notwithstanding the reduction in the volume of antibody solution. Generally, this apparatus, which is a laboratory tool, assists in more efficiently conducting the screening operation by reducing the amount of antibody solution needed, while at the same time producing wider, more easily readable, antibody stripes upon a single membrane. In addition, the apparatus may include means for substantially reducing the time necessary for performing the screening operation.